docs: def _compute_geometrical_spreading_term(self, C, rrup):
          """
          Compute magnitude scaling term as defined in equation 19, page 2291
          (Tavakoli and Pezeshk, 2005)
          """
          f2 = np.ones_like(rrup)
          idx1 = np.nonzero(rrup <= 70.)
          idx2 = np.nonzero((rrup > 70.) & (rrup <= 130.))
          idx3 = np.nonzero(rrup > 130.)
  
          f2[idx1] = (C['c9'] * np.log(rrup[idx1] + 4.5))
          f2[idx2] = (C['c10'] * np.log(rrup[idx2]/70.) +
                      C['c9'] * np.log(rrup[idx2] + 4.5))
          f2[idx3] = (C['c11'] * np.log(rrup[idx3]/130.) +
                      C['c10'] * np.log(rrup[idx3]/70.) +
                      C['c9'] * np.log(rrup[idx3] + 4.5))
          return f2